UPANIṢADS

UPANIṢADS . The Upaniṣads are codified Sanskrit philosophical speculations of varying lengths in both prose and verse form, composed orally and set to memory mostly by anonymous South Asian sages, primarily in the classical and medieval periods. While the most important and influential Vedic Upaniṣads date from the eighth to the fourth centuries bce, some lesser-known sectarian Upaniṣads appear as late as the sixteenth century ce. Individually and as a whole, the Upaniṣads present insights and doctrines that serve as the foundation for much of India's philosophical thought.

Traditional South Asian teachings based on the Upaniṣads have been called the Vedānta, the "end of the Veda," for the Upaniṣads chronologically and formally set the closure of the Vedic canon. Perhaps more to the point, Upaniṣadic lessons are said to be the end of the Veda in that they purport to present the "hidden meaning" or the "real message" of religious practice and thought.

The central teaching presented by the Upaniṣads as a whole centers on the notion that behind all of the spatial swirl and temporal flux of the world as it is experienced by the senses is a subtle, pervasive, timeless, and unchanging reality that is identical to the undying essence of the human being as well. The early Vedic Upaniṣads call this unified and imperishable world soul brahman or ātman, the former applying more typically to the godhead and the latter signifying the correlative divine "self" residing at the deepest level of one's person. The theistic Upaniṣads teach that this brahman or ātman is a single deity known generically as Īśv Īśa (Lord) living deep within one's being and identified particularly as Śiva, Viṣṇu, or the Goddess by particular sectarian communities.

While they explicitly or implicitly admit the difficulties of comprehending a hidden reality that either transcends or simply cannot be known through the structures of time, space, and causation, the Upaniṣads hold that through disciplined practices of meditation and the cultivation of extraordinary knowledge, it can in fact be discerned. Such discernment releases one from the apparent cycles of life and death caused by one's ignorance of the fact that the essential self does not die. Thus, Upaniṣadic religious anthropologies, theologies, and soteriologies all revolve around a key lesson that appears ubiquitously but that might well be characterized by the Adhyātma Upaniṣad' s assertion that "he is a free person who through insight sees no distinction between his own self and brahman, and between brahman and the universe" and the Kaṭha Upaniṣad' s proclamation that, having comprehended this identity, "one is released from the jaws of death" (3.5).

The Upaniṣads were first put into written form in 1656 ce, when Sultan Dara Shakoh sponsored the translation of fifty Upaniṣads from Sanskrit into Persian. In 1801–1802, these Persian works were then translated into Latin by Antequil du Perron, becoming the first, although poor, European version. Since that time, all of the Upaniṣads have been rendered into various Indian scripts, and the more important or influential ones have been translated into virtually all of the world's major languages. The Upaniṣads stand as works of monumental significance in the history of India and of the world.

Connotations of the Term UpaniṢad

Built from the Sanskrit verbal root sad ("sit") and the prefixes upa- and ni- ("nearby"), the word upaniṣad represents the act of sitting at the feet of someone. The pedagogical tradition in which a student in search of sacred knowledge sat on the ground in front of a guru typifies, in part, the practices of the Vedic vānaprastha s ("forest dwellers") and saṃnyāsin s ("renun-ciants") who had retired to forest retreats to meditate and study. The practice also appears in various Agamic and Tantric traditions, many of whose followers lived beyond the boundaries of settled civilization, where they practiced yogic meditation under the guidance of a guru. Through combinations of dialogues, monologues, questions and answers, riddles, and speculative discourses, the student privately heard from the teacher secret lessons that had been passed down through the generations of the sacred lineage. Such a "secret lesson" was an upaniṣad. Isolated as a textual genre, the collections of such secret teachings are known as the Upaniṣads.

The term upaniṣad thus connotes an element of esotericism. In fact, the Upaniṣads state explicitly that such lessons are not intended for the general population: "Let none who has not maintained the vow think on this," demands Muṇḍaka Upaniṣad (3.12.11), and the Rāmapūrvatāpanīya Upaniṣad warns the teacher to "give not [his lessons] to common people" (84). That the teachings were to be heard by only select ears is demonstrated by the texts themselves, for synonyms and appositions of the word upaniṣad include not only such terms as satyasya satyam ("the truth of truth," Bṛhad. Up. 2.1.20), but also rahasyam ("that which is hidden," Nṛsimhottaratāpanīya Up. 8) and paramam guhyam ("that which is a supreme secret," Kaṭh. Up. 3.17).

The esoteric tone of the Upaniṣadic teachings derives in part from the place they hold in the larger Vedic literary corpus. The earliest Vedic literatures are the inspired hymns, chants, and incantations of the Ṛgveda, Sāmaveda, Yajurveda, and Atharvaveda, which were composed by the visionaries and priests of the various Vedic traditions and codified around 1200 bce (although some are earlier and some later). To these Saṃhitās ("collections") of poems and songs are attached ritual instructions known as the Brāhmaṇas, which date to roughly 1000 to 800 bce. As early as the ninth century bce, individuals and small groups of people, most often of the kṣatriya (warrior) rather than the brāhmaṇa (priestly) class of society (see Bṛhad. Up. 1.4.11), began to leave the villages to live and meditate in the forest. There, unable or unwilling to perform the sometimes elaborate and expensive Vedic religious ceremonies, they contemplated the allegorical rather than literal significance of the hymns and rituals. These allegorical interpretations formed the basis of texts known as the Ᾱraṇyakas, or "forest books." Toward the early part of the eighth century bce these contemplative sages began to formulate more abstract philosophical interpretations of the metaphors and homologies used in the Brāhmaṇas and Ᾱraṇyakas as they sought to gain knowledge of the deeper ontological status of the world and of the place the human being holds in that world. Out of this context came the Upaniṣads, the non-sacerdotal philosophical musings on the nature of reality itself.

The composers of the Upaniṣads diverged from the religious tradition of their time in that, unlike earlier Vedic poets and visionaries, they found little interest in proclaiming the wonder of the objective world or in praising the gods said to have enlivened that world. The forest sages understood the outer world to be less significant than the inner, and the gods to be nothing more than reflections or expressions of subjective processes within one's own being. "All of the gods are within me," asserts an early forest work, the Jaiminīya Upaniṣad Brāhmaṇa (1.14.2). The Kaivalya Upaniṣad, a later text, teaches that "the highest brahman, which is all forms, which is the supreme reality of the universe, which is the most subtle of the subtle and which is eternal, is nothing but yourself." The Upaniṣadic stress on the inner world rather than on external religious practices similarly distinguished the forest sages from the composers of such ritual texts as the Brāhmaṇas and, later, the Kalpasūtras; for the forest sage had no need for "ritual baths, nor periodic rites, nor deity, nor location, nor sacred space, nor worship" (Tejobindu Up. 4).

The lines separating the Brāhmaṇas and the Ᾱraṇyakas, and the Ᾱraṇyakas and Upaniṣads, as textual genres are not distinct; the early Ᾱraṇyakas resemble in form the later Brāhmaṇas, and the later Ᾱraṇyakas are nearly indistinguishable from the early Upaniṣads. Some traditions hold that the first true Upaniṣad is the Ṛgveda's Aitareya Ᾱraṇyaka (ninth century bce), while most others mark that line with the emergence of the Śukla ("White") Yajurveda 's Bṛhadāraṇyaka Upaniṣad and the Sāmaveda 's Chāndogya Upaniṣad, both of which date to the eighth century bce.

UpaniṢadic Teachings

Symbolic representations in the Upaniṣads of ultimate reality are consistent with the notion that such reality is unmanifest yet vital. Brahman (ātman, Īśvara, etc.) is described as life-giving breath (prāṇa ), wind (vāyu ), or empty space (ākāśa ); as pure consciousness (cit ), bliss (ānanda ), or eternity (ananta ); and as the infinite subject by whom all objects are known, the "inner guide" (antaryāmin ) of all that is.

Given its acknowledged immanent yet transcendent nature, ontological discourses in the early Vedic Upaniṣads depict brahman both cosmically (saguṇa, "with characteristics") and acosmically (nirguṇa, "without characteristics"). Saguṇa brahman is understood to be the finest essence (aṇimā, rasa, etc.) of all things in the world, as honey is the essence of beeswax and oil is the essence of sesame seeds (see Ch. Up. 6.9ff.). Understood cosmically, therefore, brahman is the substance of the universe. This does not mean that brahman is the material stuff of the world that can be perceived sensually. Rather, it is the hidden and subtle reality that allows all things to exist in the first place. Thus, when the sages of the Muṇḍaka Upaniṣad note that "this whole world is brahman " and that brahman is the "hidden mover … within all that moves, breathes, and winks" (2.2.1–2), they imply the cosmic ontological notion that brahman is the very "beingness" of all beings, including the human being. Transformative insight allows one to understand that this cosmic substratum is unified and indivisible, or—as the Chāndogya Upaniṣad 's Uddālaka Ᾱruṇi teaches his son, Śvetaketu—"Thou art That!" (6.9.1–6.16.3).

Understood acosmically, brahman cannot be described through definitive or positive statements, because brahman transcends the limitations of language. Thus, nirguṇa brahman is not subject to categorization, and therefore, can neither be perceived nor conceived. Brahman "cannot be heard, nor touched. It has no form [and] is imperishable. Similarly, it has no flavor, nor odor. It is eternal, without beginning [and] without end" (Kaṭh. Up. 3.5), and it "cannot be known through language, nor by the mind, nor by sight" (6.12). That the content of ultimate reality cannot be depicted is summarized most succinctly in the Bṛhadāraṇyaka Upaniṣad 's recurring assertion that "the self [ātman ] is not this, not that" (4.4.22ff.).

Thus, while the Upaniṣadic student seeking knowledge of suguṇa brahman was to comprehend the unity of all things in a world constructed on the essence of brahman, the student who looked for an understanding of nirguṇa brahman was to "deconstruct" the phenomenal world, as it were, in order to comprehend the imperishable self that lies behind the world of life and death.

Whether they considered brahman to be cosmic or acosmic, Upaniṣadic teachers generally distrusted empirical knowledge gained through sensual experiences. According to these thinkers, the physical world is a "measured" or "constructed" world, the world of māyā, a term that in the Upaniṣads denotes those aspects of the world that are empirically perceived but not ultimately real. Māyā, in other words, characterizes the world of time, space, and causation. According to Upaniṣadic teachings, then, that world which the ignorant call the "real world" is not, in truth, real.

Upaniṣadic ontologies are thus closely linked with epistemology. They are similarly related to physiology and psychology. Drawing on Sāṃkhya metaphysics, the Upaniṣads generally recognize a dualism of matter (prakṛti ) and spirit (puruṣa ). The former constitutes the objective and phenomenal world. The latter comprises the knowing subject that has no temporal or spatial limitations, and at times is used as a synonym for ātman. Within the world of prakṛti, the human body and mind may be divided into the gross body (sthūla-śarīra ) and the subtle body (sukṣma- or liṅga-śarīra ). Everyday consciousness revolves around the gross body made up of the senses and the objects of those senses (known collectively as the indriya s). Sensations gained from the gross body are then categorized by the subtle body, which consists of the mind (manas ), the mechanism of personal identity or "ego" (ahaṃkāra ), and the "awareness" (buddhi or antaḥkāraṇa ), the basis of one's ability to live and act in the world.

Upaniṣadic physiology declares that both the gross and subtle bodies, however, are phenomenal (and therefore unreal) constructions relative to the spirit, the true self (see Kaṭh. Up. 3.10–11). Thus, the farther one's awareness is removed from its attachment to the external world experienced by the gross and subtle bodies, the closer one comes to a full yet nonempirical experience of the true self. Accordingly, the Upaniṣads emphasize the importance of dream states in the comprehension of deeper realities (see, e.g., Bṛhad. Up. 4.3.9). In sleep one loses awareness of the outside world, a world that is in effect a bad dream to begin with. The deeper one sleeps, the closer to eternal reality one gets.

The Upaniṣads recognize four states of waking and dreaming awareness, each successively purer and closer to the direct comprehension of ātman. The grossest psychological level is that of waking consciousness, a level in which apparent objects are mistakenly understood to be distinct entities and in which the subject does not recognize itself. The second, more refined, level of awareness is that of active dreaming, a state in which objects lose their solidity and appear more as they really are—as changing and unreal events. The dreaming subject is a "creator" (kartṛ ) of the world, which exists only because he "projects" (sṛjate ) it (see Brhd. Up. 4.3.10). The third level is that of dreamless sleep (samprasāda, suṣupti ), in which one loses all awareness of oneself as an object in relation to other objects and no longer experiences the constrictions of time and space. In dreamless sleep one is said to have gained complete tranquillity. Here, one momentarily enjoys complete reunion with brahman and experiences, albeit nonempirically, the highest bliss (paramānanda; see Bṛhad. Up. 4.3.32).

Later Upaniṣads, especially those influenced by the practices and ideologies of Yoga, add to these states another level to one's psychological being, known simply as turīya or turya, "the fourth." Maṇḍukya Upaniṣad 7 describes this state: "It is not cognitive, nor is it noncognitive. It is unseen, unable to be spoken of, ungraspable, without any distinguishing characteristics, unthinkable, unnameable. It is the essence of the knowledge of the One Self [ekātma-pratyaya-sāram ], that into which the world resolves. It is peaceful and benign. It is indivisible." Such a state sounds like the Upaniṣadic notion of ultimate reality. Indeed, the passage continues: "It [turīya ] is ātman. It is to be known."

The waking somatic body, therefore, is unreal relative to ultimate reality, a point that carries ethical and eschatological implications. The "self" of one's being leaves the body at death, as the mango fruit at maturity separates from its stalk (see Bṛhad. Up. 4.3.36). If one has not renounced one's attachment to the world of the senses, then one will be reborn in another physical body, the existential situations of which are determined by the ethical laws of karman; and sooner or later one will suffer and die again. This continually turning wheel of death and rebirth (saṃsāra ) is understood to be a painful trap from which one is released only when one understands that the physical body is not the real self, and that the world which the senses perceive is an insubstantial and effervescent illusion.

Most of the Upaniṣads agree that the best way one would cultivate such a freeing insight would be through the rigors of yogic meditation. While the Vedic Upaniṣads as a whole reflect the influence of yogic practice and ideology (see, for example, Maitri Up. 6.19–30 or Śvet. Up. 2.8–10), it is in the Yoga Upaniṣads that such teachings are most fully presented. For example, the Amṛtabindhu, Śāṇḍilya, and Yogatattva Upaniṣads, among others, contain long passages on the eight "branches" (aṣṭānga ) of yogic practice (discipline, self-restraint, correct body posture, breath control, suppression of sensory awareness, mental concentration, intuitive meditation, and final union with the Absolute), the proper means to master each, and the characteristics of the successive levels of yogic "powers" (siddhi s) one gains as one becomes more adept at the particular practices.

While continuing to uphold the efficacy of yogic practice, some of the Upaniṣads also present the more theistic teaching that one cannot truly know one's soul without what might be termed the "grace" of the soul. Such appears to be the position of Kaṭha Upaniṣad 2.23, which maintains that "this soul [ātman ] cannot be attained through instruction, nor through rational thinking, nor by great learning. He is to be attained only by the one whom [the supreme self] chooses. The soul [ātman ] reveals his own nature to such a one." The soteriological dimensions of this theistic teaching are much more explicit in the Śvetāśvatara Upaniṣad 's statement that "more subtle than the subtle, greater than the great, is the soul [ātman ] that is set within the heart of the creature. One beholds it to be actionless and becomes free of sorrow, when through the grace of the Creator [dhātuḥ prasadāt ] he sees the Lord [Īś ] and his greatness" (3.20).

Classification of the UpaniṢads

It is somewhat problematic to arrive at a precise number of Upaniṣads, because if all Sanskrit works claiming to present secret teachings were to be classified as Upaniṣads the number would be indefinite. Nearly 250 texts call themselves Upaniṣads—including the Allopaniṣad ("secret teachings about Allāh," composed at the time of Akbar) and the Christopaniṣad, dated well after the rise of Christian communities on the subcontinent—but it appears that most of these do so merely as a way to align themselves with a respected literary genre or religious tradition.

The Muktika Upaniṣad and other medieval South Indian works mention 108 separate Upaniṣads in an enumeration that has become somewhat of a stock list. Using the methods of historical, thematic, and textual criticism, twentieth-century scholars have isolated 123 genuine Upaniṣads. These works may be classified into two general categories, the Vedic Upaniṣads and the later Upaniṣads.

The Vedic Upaniṣads

Virtually all Vedic and most sectarian traditions recognize ten to eighteen Upaniṣads as revealed authoritative scripture (śrūti). Furthermore, all of the more important traditional theologians and philosophers throughout classical and medieval India recognized the central importance of these ancient works, and have written extensive commentaries on them. For these reasons, the Vedic Upaniṣads have also been called the Major, or Principal, Upaniṣads. They may be divided into three historical and textual groups.

1

The earliest Upaniṣads (the Bṛhadāraṇyaka, Chāndogya, Taittīriya, Aitareya, and Kauṣītaki Upaniṣads and the prose parts of the Kena Upaniṣad ) predate the rise of Buddhism in the sixth century bce, the Bṛhadāraṇyaka and the Chāndogya being the earliest and the Kena being the latest. All are explicitly aligned with one or another of the various sakhā s, or "schools" of Vedic interpretation, and are composed in a prose that closely resembles Vedic Sanskrit. These texts make frequent use of allegorical modes of interpretation and are often almost indistinguishable in style from the Ᾱraṇyakas. In many ways these six works serve as the philosophical foundation for all of the later Upaniṣads.

2

A second group of Upaniṣads (the Kaṭha [or Kaṭhakā ], Īśa, Śvetāśvatara, Muṇḍaka, and Mahānārāyaṇa Upaniṣads and the metrical parts of the Kena Upaniṣad ) reflects a growing sectarian orientation and dates to the sixth and fifth centuries bce. These works, which are composed primarily in verse, are only loosely attached to the Vedic sakhā s, and make less use of metaphorical, allegorical, or other tropic means of expression.

3

The Upaniṣads of a third group (the Praśna, Maitri [or Maitrāyaṇīya ], Jābāla, Paiṅgala, and Māṇḍūkya Upaniṣads) return to prose form, but in a language that resembles classical Sanskrit much more than Vedic Sanskrit. They probably emerged in the late fifth and early fourth centuries bce although the dates for a few of them are uncertain.

All of these works are attached to the textual collections of specific priestly Vedic traditions. The Aitareya and Kauṣītaki Upaniṣads belong to the Ṛgveda. The Kaṭha, Maitri, Taittrīya, and Śvetāśvatara Upaniṣads are attached to the Kṛṣṇa ("Black") Yajurveda, while the Bṛhadāraṇyaka Īśa, and Paiṅgala Upaniṣads are aligned with the Śukla ("White") Yajurveda. The Chāndogya and Kena Upaniṣads belong to the Sāmaveda, and, finally, the Muṇḍaka, Māṇḍūkya, Praśna, and Jābāla Upaniṣads form a part of the conclusion of the Atharvaveda.

The later Upaniṣads

To this list of principal Vedic Upaniṣads most authorities would add a large number of less known and, for the most part, medieval works that may be classified as the later Upaniṣads. These works are not universally accepted as śrūti, and they have not received the extensive attention from traditional South Asian philosophical commentators as have the Vedic Upaniṣads. This does not mean that they are less important than others. Indeed, these texts may well be more influential in their respective communities than the principal Vedic Upaniṣads. Such works reflect the increasing influence of Sāṃkhya philosophy, Yoga practice and ideology, and sectarian theistic traditions through the classical and medieval periods. While many align themselves with the Ṛgveda, Yajurveda, or Sāmaveda, most of these Upaniṣads are attached, at least nominally, to the Atharvaveda. Most are in prose form and are composed almost entirely in classical Sanskrit.

The number of the later Upaniṣads is too large to list all of them here. Only the most important or representative ones will be mentioned; readers seeking a more complete list are directed to the bibliography.

1

Vedānta Upaniṣads. These works, which include the Muktika, Piṇḍa, Garba, Ātman, Prāṇāgnihotra, Adhyatman, and Brahmā as well as perhaps two dozen other Upaniṣads, fairly consistently maintain the general doctrines presented by the Vedic Upaniṣads, and show relatively little sectarian influence. They differ from the Vedic Upaniṣads only in that they are not cited in traditional commentaries.

2

Yoga Upaniṣads. These texts arose out of a more specifically ascetic context than did many of the Vedic and Vedānta Upaniṣads, and reflect the influence of Yoga ideologies and practices within Upaniṣadic circles. This group includes the Yogakuṇḍalī, Nādabindhu, Śāndilya, Yogatattva, Tejobindhu, Haṃsa, Amṛtabindhu, Dhyānabindhu, and Varāha Upaniṣads. These works center on the direct experience of the eternal self (ātman ) through specific techniques of Yoga and through the meditation on the sacred syllable om.

3

Saṃnyāsa Upaniṣads. These works tend to extol the life of the wandering ascetic's search for release from the cycle of rebirth (saṃsāra ) and teach ways in which such release may be obtained. They include the Nāradaparivrājaka, Bhikṣuka, Paramahaṃsa, Ᾱśrama, and Saṃnyāsa Upaniṣads.

4

Mantra Upaniṣads. These teachings center on esoteric interpretations of specific sounds and syllables and place those interpretations into Yogic as well as Śaiva, Vaiṣṇava, and Durgā theistic contexts. Typical of such works would be the Tārasāra, Kalisantāraṇa, and Nārāyaṇa Upaniṣads.

5

Śaiva Upaniṣads. The earliest Śaiva Upaniṣad might well be said to be the Vedic Śvetāśvatara Upaniṣad, which praised the role of Rudra (a Vedic precursor to the god Śiva) in the religious quest. The more well-known of the medieval Śaiva Upaniṣads would include the Nīlarudra, Kālāgnirudra, Kaivalya, and Atharvaśiras Upaniṣads, all of which understand the person of Śiva (also known as Maheśvara, Bhairava, Īśana, and other names) to be an embodiment of the deepest self, ātman.

6

Vaiṣṇava Upaniṣads. These texts tend to interpret the various incarnations of the god Viṣṇu as representative forms of the ātman. Some Vaiṣṇava traditions look to the Īśa Upaniṣad as the Vedic antecedent to, or oldest sectarian representative of, this particular genre. Works associated with this group include the Nṛsimha-pūrvatāpanīya, Nṛsimhot-taratāpanīya, Mahā, Rāmapur-vatāpanīya, and Ramottara-tāpanīya Upaniṣads.

See Also

Brahman; Māyā; Samādhi; Saṃnyāsa; Soul, article on Indian Concepts; Vedānta; Yoga.

Bibliography

Readers seeking a stock list of what have been termed Vedic and later Upaniṣads should turn to the opening lines of the Muktika Upaniṣad, which lists 108 such works. J. N. Farquhar, a historian of Indian religious literatures, has distinguished 123 distinct Upaniṣads, which he lists in his An Outline of the Religious Literature of India (1920; reprint, Delhi, 1967), p. 364.

The last hundred years have seen the publication of a large number of Upaniṣads in modern languages, many of which suffer from a lack of perspicuity due to the somewhat esoteric nature of the original works. The most objective English translation of most of the Vedic Upaniṣads remains Robert Ernest Hume's somewhat stilted The Thirteen Principal Upanishads, 2d rev. ed. (Oxford, 1949). A more fluid translation is Sarvepalli Radhakrishnan's The Principal Upaniṣads (New York, 1953). Radhakrishnan's work is better than Hume's in that it includes the Sanskrit and it translates sixteen rather than thirteen works. Some students will find Radhakrishnan's commentaries on the works to be of some help, although many of them reflect his neo-Vedantic bias. Another good translation, and one that openly admits an Advaitic point of view, is Swāmī Nikhilānanda's The Upanishads, 4 vols. (New York, 1949–1959). Readers interested in the later Upaniṣads would be advised to look to Paul Deussen's Sechzig Upanishads des Veda (Leipzig, 1897), to K. Nārāyanasvāmi Aiyar's Thirty Minor Upanishads (Madras, 1914), and to Jean Varenne's Upanishads du yoga (Paris, 1974). Readers seeking only selections from the Vedic Upaniṣads might turn to Sarvepalli Radhakrishnan and Charles Moore's edited volume, A Source Book in Indian Philosophy (Princeton, N.J., 1957), pp. 37–96, or to Juan Mascaró's The Upanishads (Baltimore, 1965), although the latter is somewhat colored by a theistic understanding of the texts.

Those readers interested in short introductions to Upaniṣadic thought are advised to consult Paul Deussen's The Philosophy of the Upanishads (1906), 2d ed., translated by A. S. Geden (New York, 1966); Arthur Berriedale Keith's The Religion and Philosophy of the Veda and Upanishads, 2 vols. (1925), 2d ed. (Westport, Conn., 1971), pp. 551–570; or to Surendranath Dasgupta's A History of Indian Philosophy, vol. 1 (1922; reprint, Cambridge, 1951), pp. 28–61.

William K. Mahony (1987)